Label-free isolation of circulating tumor cells using negative lateral dielectrophoresis- assisted inertial microfluidics

Abstract

In this study, a dielectrophoresis (DEP)-assisted inertial microfluidics methodology was introduced for the the isolation of circulating tumor cells (CTCs) from diluted blood samples. The methodology was based on the negative DEP, provided with the laterally allocated microelectrodes as well as the proper selection of the applied electric field frequency and voltage, to suppress the limited purity arising from the overlapped sizes of CTCs and white blood cells. Initially, the dynamics of 5 and 15 µm polystyrene microparticles within the DEP-assisted inertial microfluidic device were numerically and expimentally investigated. While the dynamics of the larger microparticles was governed by the inertial and DEP forces, those of the smaller microparticles were subject to the Dean drag force. In the absence of the DEP force, the larger microparticles migrate to two stable equilibrium positions corresponding to the upper and lower walls for the microchannel cross-section. In the presence of the DEP force, the equilibrium position corresponding to the lower wall is considerably displaced, while the equilibrium position corresponding to the top wall remains almost intact. Finally, it was found that the methodology outperformed the corresponding solely-inertial methodology in terms of purity for the isolation of CTCs from diluted blood samples. For instance, the purity of isolated MDA-MB-231 spiked in diluted blood samples, at a hematocrit of 1%, by the solely-inertial microfluidic device was 85.3%, while viable CTCs were captured using the DEP-assisted inertial microfluidic device with 94.1% purity at the total flow rate and applied voltage of, respectively, 650 µL min− 1 and 50 V.